The semiconductor industry is continuously moving toward the fabrication of smaller and more complex microelectronic components with higher performance. The production of smaller integrated circuits requires the development of smaller electronic components, and closer spacing of those electronic components within the integrated circuits. Memory cells are an important part of many microelectronic components, and smaller and more reliable memory cells are desirable. One type of memory cell is a flash memory cell which is a nonvolatile and re-writable memory cell. Non-volatile memory cells retain stored information even when the memory cell is de-powered, and stored information can be changed when the memory cell is re-writable. buried insulator
Some integrated circuits include fully depleted semiconductor-on-insulator (FDSOI) transistors that have advantages over transistors that do not include a fully depleted channel, such as reduced short channel effects and reduced parasitic capacitances. These integrated circuits may utilize a semiconductor-on-insulator (SOI) substrate that has a shallow active layer overlying a buried insulator layer. Memory cells produced in conjunction with the FDSOI transistors utilize the SOI substrate with the very shallow active layer, so the memory cell is designed accordingly. The shallow active layer may present challenges for non-volatile memory cells. For example, holes generated by impact ionization during channel hot-electron injection may produce a positive bias in the floating body, which in turn may decrease the threshold voltage. This has been referred to as the “kink” effect. The kink effect may be more pronounces in partially drained semiconductor-on-insulator (PDSOI) substrates. Furthermore, very high voltages may be required to influence the memory cell through the buried insulator layer for erase operations.
Accordingly, it is desirable to provide integrated circuits including semiconductor-on-insulator substrates with memory cells having higher threshold voltages, and methods of producing the same. In addition, it is desirable to provide integrated circuits on semiconductor-on-insulator substrates with memory cells that require traditional erase voltages, as compared to integrated circuits with the high erase voltages required to influence a channel through a buried oxide layer. It is desirable to provide methods of producing the same. Furthermore, other desirable features and characteristics of the present embodiment will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.